165555666 has 12 divisors (see below), whose sum is σ = 358703982. Its totient is φ = 55185216.

The previous prime is 165555659. The next prime is 165555739. The reversal of 165555666 is 666555561.

It can be written as a sum of positive squares in only one way, i.e., 159896025 + 5659641 = 12645^2 + 2379^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4598751 + ... + 4598786.

Almost surely, 2^165555666 is an apocalyptic number.

165555666 is an abundant number, since it is smaller than the sum of its proper divisors (193148316).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165555666 is a wasteful number, since it uses less digits than its factorization.

165555666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9197545 (or 9197542 counting only the distinct ones).

The product of its digits is 810000, while the sum is 45.

The square root of 165555666 is about 12866.8436689034. The cubic root of 165555666 is about 549.0956664882.

The spelling of 165555666 in words is "one hundred sixty-five million, five hundred fifty-five thousand, six hundred sixty-six".